The proposed research project is concerned with speech sound perception in infants from six to twelve weeks of age. One objective of the research is to expand the normative data base on infant speech sound perception. The perceptability of two speech sound contrasts will be tested which have not yet been included in work of this kind, the contrast /m/ vs. /n/ and the contrast /s/ vs. /s/. A second objective of the study will be to pilot test a procedure for assessing infant speech sound perception across a wide age range. Results using the new non-contingent sucking procedure will be compared with results using a commonly used contingent procedure. Favorable results using the new procedure will indicate its potential usefulness as a test procedure for future work of this kind.